compression test correction

[hassenhassen]

hi everybody
i am a newbie in mechanical charaterisation of the metal sheet.
i am working on a compression test using an universal compression test (model PROETI 200KN with the software HOYWIN(R)).
i performed a test without specimen to obtain the curve of the dispacement load of the stiffness of the compression machine (as showed in figure 1).
after that i used the option "find automatically the displacement of the origine" by using user interface in the software HOYWIN(R) installed for the compression machine (as showed in figure 2).
after that i performed my compression punch process and i obtained the curve showed in figure 3.
All the figure 1-2-3 are presented in the attached file.
My questions are:
1- how to correct the curve displacement-load of the stifness of the compression machine
2- how to use the option of the calculation of the new displacement origine in the software of the machine? is it necessary to correct the curve of the machine stifness and configure the machine with this new origine for the next tests?
3- how to correct the curve of my compression punch process in order to have the true load-displacement curve .
4- what is the explanation of the first part of the obtained curves as showed in figure 4.

thank you for your comprehention and your help

 

[JStephen]

Can't open the attachment.
Your question seems VERY specific to a particular machine and field of endeavor, so I'm not sure how much help you'll find on it even at that. It could fall under mechanical or industrial engineering as well.

 

[hassenhassen]

hi
thank you for your answer
my question is not specific for one machine but it is a process used to correct the obtained curve of the experiment test .
the issue is how to correct the obtained stifness curve of the compression machine and how to use is to correct the obtained curve of the compression punching process on the speciment.

the attached file is ok and you can download it and open it now. it is a winrar file.